Telephone-receiver cap



new 0R 1,732,045 f l5, 1929. G, B FRENCH 11,732,043

TELEPHONE RECEIVER CAP Filed Jan. 12, 1929 F /f 5 n M l I lNVENTORfQ,

BY` A Patented Oct. 15, 1929 UNTED STATES n GEORGE B. FRENCH, OF SOUTHAMPTON, NEW YORK, ASSIGNOR TO FRENCH ELECTRIC COMPANY INC., A. CORPORATION OF NEW YORK TELEPHONE-RECEVER CAP Application filed January 12, 1929. Serial No. 332,044.

This improvement relates more particularly to the provision of means for preventing excessive air pressure on the ear drum, as a result of the movements of the diaphragm.

It has been found that holding the telephone receiver too tightly against the ear often annoys the person listening with the receiver, because of the air pulsations in a substantially closed chamber produce undue pressure against the ear drum. Attempts have been made to overcome this by notches and holes in the ordinary funnel type of re-/ ceiver cap, wherein there is provided ai" trumpet-like or conical passage to the central portion of the diaphragm, forming with the ear, an air chamber of considerable volume. But it has been found that this ordinary type of receiver is not suitable or desirable for use of the deaf or people hard-of\ hearing, and any provision associated therewith for relieving excess pressure in the air chamber and on the ear drum is not applicable to a thin model receiver.

Therefore, the object of the present inven tion is to provide the cap of a specially constructed fiat type telephone receiver withair relief channels, and this is preferably ac-I complished by radial kerfs, slots or openings, extending substantially to the level of the outer face of a thin flat Idisc forming the covering in front of the diaphragm.

The preferred form of the improvement is shown in the accompanying drawings, in which Fig. l is a plan view of the front of the telephone receiver cap; Fig. 2 is a side view of the telephone receiver with the cover cap in place and Fig. 3 is a vertical sectional view of the telephone receiver cap.

Referring to the drawings, it will be seen that the telephone receiver cap of this invention comprises substantially an annular body portion A with a counter-board flange or skirt portion which is screw-threaded at B for attachment to the receiver casing C,

y substantially as shown in Fig. 2. The cap is provided with a shoulder D which, when the cap is screwed on the casing C, is adapted to clamp the usual diaphragm in place. An air chamber is adapted to be formed in the body of the cap, in front of the diaphragm, by a circular recess or bore E, the outer extent of this chamber being limited by a thin l'lat disc cover portion F, substantially as shown in Fig. 3. The disc cover portion F of the cap is provided with a central opening G, for the escape of the sound waves, set up by the vibrating diaphragm.

Annularly of the disc portion F of the cap the body portion A is substantially circular (about three-quarters of a circle) in cross-section and part of the circular portion projects outward from the face of the disc F to form a bead, ledge or rim H of semicircular cross-section relative to the face of the thin cover disc F and extending circumferentially of the latter.

The thin flat type of receiver, such as here shown, is more particularly adapted for use of the deaf or people hard-of-hearing, because, for such use, it is particularly important to have the receiver as inconspicuous as possible. Furthermore, receivers of this type are sometimes worn on the ear for an extended time and in close contact therewith, that is, substantially air tight. The ordinary receiver, when so worn, gives a humming and roaring sound and the ear drum is liable to be injured by the alternate increase and decrease of air pressure due to the vibrations of the diaphragm. This is not only annoying to the user, but it has a tendency to reduce the eiiiciency of the receiver by preventing the correct transmission of the sound waves, thus rendering more difficult a proper interpretation of the Sounds.

Tn order to overcome these objections and, at the same time, provide a flat telephone receiver, especially adapted for use of the deaf or people hard-of-hearing, the annular bead or ledge H is provided with a plurality of openings, preferably extending radially and formed, in the present instance, by radial kerfs or slots K. Six of these are shown in the drawings, but obviously, the number of the slots and the width thereof may be varied, but it is preferable that the slots should be relatively narrow.

In order to support the receiver by means of a head band or the like, an annular groove or notch L is provided, in which the necessary holding clips may be inserted. It will be observed that the thin disc portion F of the cover cap is substantially co-extensive with the exposed portion of the diaphragm, as determined by the peripheral Wall 0I" the air chamber E.

It will be seen that a particularly flat type of telephone receiver is provided, in the construction shown, and the opening G in the thin cover disc F provides for the escape of the sound waves resulting from the vibrations of the diaphragm. rlhe lateral openings or slots K in the bead or rim H provide vents which relieve the air pressure in the air chamber E and prevent the air confined between the cap disc F and the ear drum from being compressed, thus providing for sonorous and perfect transmission of the sounds emitted by the vibrating diaphragm without injury or discomfort to the user. rIhe provision oi the radial openings K permit the receiver to be worn by the user for an indeiinite period without undue annoyance from drumming or other aggravating sounds and particularly extraneous sounds, which might arise if the receiver were not held closely to the ear. -l/Vith the present improvement, it will be seen that the receiver may be held closely to the ear without discomfort for openings K are so small that they are scarcely noticed yet they serve to relieve the pressure without annoying the wea-rer with drumming noises or interfering sounds from the outside.

It will be understood that the preferred form of the improvement has been shown in the accompanying drawings.y but the invention is not limited to the specific arrangement or construction shown, for various modifications may be made therein without departing from the spirit and scope of the invention.

I claim l. A telephone receiver cap comprising an annular body portion provided with a circular air chamber, a relatively thin flat disc forming the front wall of the air chamber and substantially coeXtensive with the periphery of said air chamber, and a raised bead of semi-circular cross-section extending around the periphery of said disc, and provided with a plurality of radially eX- tending openings for the purpose described.

2. A telephone receiver cap comprising an annular body portion provided with an air chamber adapted to lie in front of the diaphragm, a thin disc cover, adapted to eX- tend parallel with the diaphragm and substantially coextensive with said air chamber, said disc being provided with a central opening, and an annular raised ledge extending peripherally of said disc and integral therewith and with said body portion, said peripheral ledge being provided with a plurality of radial slots extending down to the outer face of said cover disc.

3. A telephone receiver cap comprising a body portion adapted to provide an air chamber over the diaphragm, the relative thickness ot said chamber being limited by a thin fiat cover disc adapted to lie parallel with the diaphragm and provided with a central opening, and an annular rim extending from the peripheral edge and outward from the face of said cover disc, said rim being provided with a plurality or radial openings, the bottoms of which are substantially coincident with said face of the cover disc for the purpose described.

4. The telephone receiver cap according to claim 3, in which the radial openings are formed by a plurality of narrow radial kerfs equally spaced circumierentially of said rim.

GEORGE B. FRENCH. 

